Core A has been a critical element in this Program Project since .its inception. There are two components to this core. The CHS portion of Core A provides human native and modified lipoproteins (and lipoprotein deficient serum) and leukocytes, human and mouse endothelial cells, and general services to the Projects and other Cores. The MRL portion of Core A provides analytical chemistry assays for the Projects and other Cores. This core is a cost-effective way of providing these essential services to the component Projects and other cores.